1. Field of the Invention
The present invention relates to a metal cable.
2. Description of the Prior Art
Metal cable is frequently used in brake assembly of bicycle or motorbike. Metal cable is used for activating brake clamp when user grabs and presses handle of the brake assembly. Conventionally, metal cable is manufactured by twisting several metal wires. To obtain batter operation performance, metal cable which has lowered friction, minimized elongation, and greater flexibility is desired.
To reduce friction caused in operation, metal cable, as disclosed in U.S. Pat. No. 986,817, is entwisted with several flat wires at outer surface thereof. However, differentiated outer layer which has specified appearance would peel off easily.
Additionally, some metal cables, as disclosed in U.S. Pat. No. 3,778,993 and U.S. Pat. No. 4,311,001, are prepared with smoothened outer surface by pressing and deforming outer wires thereof. However, such serious deformation causes not only troubles in manufacturing, but damage in mechanical properties such as elongation coefficient. Moreover, the metal cables provided are still covered be lines and veins. Friction and abrasion would still occur in operation.
Another metal cable, as described in U.S. Pat. No. 4,809,492, is provided with several elliptical wires. The elliptical wires are twisted on the central cable. Thus, outer surface is smoothened and veins on the outer surface are lessened. However, interval vacant space takes a considerable space in the cable. Effective cross section area of the wire is descended. As a result, mechanical properties of the metal cable are also damaged.
The present invention is, therefore, arisen to obviate or at least mitigate the above mentioned disadvantages.